Research on TITO Coupling Control Strategy for Parallel Hybrid Excavator

The hybridization and electrification of powertrains gain increasing popularity in recent years, especially in the field of construction machine. In this paper, a TITO (Two-input Two-Output) coupling control strategy for parallel hybrid excavator is studied. First, the structure and configuration of the parallel hybrid powertrain are introduced. Then, a TITO coupling control strategy is presented. Engine speed and SOC (State of Charge) of super capacitor are controlled by engine torque and ISG torque together. Whereafter, the model of powertrain and control strategy is built in Matlab/Simulink. Then, networked control system for parallel hybrid excavator is introduced. Finally, the control strategy is optimized and validated by field tests. The results show that the operating region is close to the high efficiency working point and SOC of super capacitor maintains within 50% and 70%. Compared with conventional hydraulic excavator, a 15% reduction in fuel consumption is achieved.